The present invention relates generally to board-to-board connectors, and more particularly to a connector assembly for connecting two circuit boards together and which prevents the two connector components from being separated from each other after they are engaged together, to thereby improve the stability of contact and a contact force between the contacts of the connectors.
As is generally known in the art, a printed circuit board (xe2x80x9cPCBxe2x80x9d) is a thin board on which chips or other electronic devices are installed. The printed circuit board is typically made from a fiberglass, and devices mounted on the board are electrically connected to each other through one or more circuits formed from copper on the circuit board. In the industry, the main circuit board in a system is called the main board or xe2x80x9cmotherboardxe2x80x9d, and secondary circuit boards that are connected to the main board are called xe2x80x9cdaughterxe2x80x9d boards or edge cards. Individual electronic parts were connected to each other on circuit board of the 1960""s, while in the 1990""s; a plurality of chips, each of which contains several ten to several million basic electronic devices, are commonly connected to each other.
In manufacturing of the circuit boards described above, a thin copper plate is first placed on a substrate made from fiberglass or plastic, and then is covered by a photoresist solution. Light is shined on the photoresist through a negative film on which a circuit is printed, and hardens portions of the photoresist coating that correspond to the circuit and which remain even after etching of the circuit board. Thereafter, the etched substrate board is passed through an electrolyte solution containing strong acid, so that the rest of the portion which is not hardened, washes away. This process completes the printed circuit on the boar The pre-designed circuit pattern permits electronic devices to be soldered, or otherwise attached, to the circuit board.
FIG. 1 illustrates, in sectional view,; a conventional board-to-board connector assembly assembled together and connecting two circuit boards 14a, 14b together. The connector assembly includes a first connector 6, typically referred to as a xe2x80x9cplugxe2x80x9d connector that is received within a recess, or chamber 4, that is formed at a center of a housing 2 of a second connector, typically referred to in the art as a xe2x80x9creceptaclexe2x80x9d connector. For this construction, sidewalls 8 are formed at both sides of the connector housing 2, and conductive terminals 10 are fixed to the sidewalls 8, while a set of opposing conductive terminals 12 are disposed in the body of the first, or plug, connector 6. The receptacle connector housing 2 is fixed to one circuit board 14a at one side, while the plug connector body 6 is fixed to a second circuit board 14b on its other side.
Each of the receptacle terminals 10 has a tail portion 10a for mounting to the circuit board and a contact portion 10b integrally connected thereto, and is bent twice upon itself so as to define two curved portions 10c and 10d that extend vertically in the contact portion 10b, and a convex contact face 10e is formed at a distal end of the contact portion 10b. Each of the plug connector terminals 12 has a vertical contact portion 12e that opposes the convex contact face 10e, which substantially has a shape similar to the symbol xe2x80x9c∂xe2x80x9d, so that a tail portion 12a of the plug connector terminal is located at an upper position in opposition to the circuit board 14a. 
However, in the case of the plug terminal having the above type of construction, when the contact portion loses elasticity due to an a external impact, the contact portion may not, maintain its contact with the convex contact face, thereby causing a problem of defective contact. Furthermore, another problem occurs in that the contact portion of the plug pin and the convex contact face 10e of the receptacle terminal 10 may be easily separated from each other by an external impact, since there its construction is not capable of securing reliable contact between the contact portions of the plug connector terminals and the convex, contact faces of the receptacle connector terminals.
The present invention is directed to a connector assembly that overcomes the afore mentioned disadvantages
Accordingly, it is a general object of the present invention to provide a connector assembly for connecting together two printed circuit boards in a manner which prevents the two connectors from easily being separated each other after they are assembled together.
Another object of the present invention to provide a connector assembly for connecting, two circuit boards together, the connector assembly including first and second mating connectors, and in which the terminals of the first connector have contact portions which are resilient in both vertical and horizontal directions so as to improve the contact force between the mating terminals of the two connectors.
It is a further object of the present invention to provide a connector assembly for connecting together two circuit boards, in which the terminals of the two connectors that make up the connector assembly can be elastically deformed, so as to improve the stability of the mating contact between the two connectors and the contact force between the two connector terminals.
Yet another object of the present invention is to provide an improved board-to-board connector assembly for connecting two circuit boards together, the connector assembly, including a receptacle connector and a plug connector, each of the two connectors having a plurality of conductive terminals, the terminals of the two connectors having configurations which reduces the overall height of the connector assembly and which can be fixed to each other, without the need to form a separate locking structure in the insulative housings, of either of the two connectors.
A still further object of the present invention is to provide a board-to-board connector assembly having a receptacle connector that mates with an opposing plug connector, one of the connectors having a plurality of conductive terminals with a xe2x80x9cZxe2x80x9d shape, or configuration, the terminal configuration reducing the overall height of the connector assembly and increasing the retention force that retains the two connectors together.
In order to accomplish these and other objects and advantages, the present invention includes in its preferred embodiment, a connector assembly for connecting together two printed circuit boards that includes a first connector having a housing for attachment to a first one of the two printed circuit boards and a second connector having a housing for attachment to the second one of the two printed circuit boards, one of the two connectors preferably being of the receptacle style and the other of the two connector preferably being of the plug style, the plug connector fitting within the receptacle connector when the two connectors are engaged together.
The first connector housing may be a receptacle-style connector, and as such, includes a base plate with sidewalls disposed at opposite sides of the base plate to form a receiving chamber, or receptacle, in the center of the -base plate, each of the sidewalls having a plurality of holes disposed therein that each receive a single conductive terminal. Each of the receptacle connector terminals preferably includes a tail section that extends out of the connector housing for attaching to the one circuit board, and an elastic contact section extending from the tail portion section within the receptacle of the connector housing, the elastic contact section being bent at least twice so as to have a plurality of elastic curved portions, the elastic contact section further having a free end with a tip thereof end bent inward to form a curved, or convex, contact face of the terminal portion. The tail section of the receptacle connector terminals extend outside of the housing sidewalls when they are inserted into the receptacle connector housing, while the contact sections thereof extend within the connector housing.
The second connector housing is of the plug-style and include a central body portion that extends from a base plate that is attached to a second circuit board. The central body portion of the plug-style connector is received within the receptacle of the receptacle housing and a plurality of conductive terminals are mounted on the plug connector central body portion. Tail sections of these terminals extend out of the body portion for attaching the plug connector to the second circuit board, while contact sections extend from the tail sections along the body portion in opposition to the terminals of the receptacle connector.
The plug connector terminals each have a curved, or convex contact face that extends outwardly and is disposed between two inclined extents of the terminals so that it may deflect, or be elastically deformed in the horizontal direction when the plug connector is inserted into the receptacle connector. The convex contact faces of the plug connector tennis pin are located between two inclined extents of the terminals so that upper surfaces of the terminal contact sections are in contact with the contact face of the receptacle connector terminals when the plug and receptacle connectors are assembled together.
It is preferred that the convex contact faces of the plug connector terminals are flanked by at least one inclined surface, so that the plug terminals may be easily and elastically deformed in horizontal and vertical directions by the receptacle connector terminals when the plug and receptacle connector housings are assembled together, so that the convex contact faces of the plug connector terminals slide over and along the contact portion faces of the receptacle connector terminals.
These and other objects, features and advantages of the present invention will be clearly understood through a consideration of the following detailed description.